Mobile communication systems in which mobile communication terminals, such as user equipment (UE) or mobile stations (MS), communicate with a network infrastructure via connections to network elements, such as to node-Bs or base stations, are well-known. In such mobile communication systems, mobile terminals typically roam and are not fixed in geographical location. As the mobile terminal roams, there is a need to adapt the node-B or base station to which a mobile terminal is connected to ensure that a reliable connection is maintained.
It is known in the art for mobile terminals to detect the strength of signals received from one or more node-Bs or base stations, and compile a report which may be returned to the network with the detected signal strength information. Based on this signal strength information the network is able to determine which node-B or base station the mobile terminal should preferably be connected to.
It is also known in the art for a full band scan to be invoked during a user equipment's cell detection process either when the user equipment fails to detect cells on a list of candidate channels or if it does not have such a list of candidate channels for a particular band. The scans comprise a number of successive search phases, the first of which is usually a so-called received signal strength indication (RSSI) scan. An RSSI scan identifies candidate channels and on which to perform further searches, by estimating the power received on each channel and detecting local peaks within this power spectrum.
It is highly desirable for RSSI scans to reliably detect carriers at levels right down to reference sensitivity, as this minimizes the time it can take for a user equipment to register and attach to a serving cell. If a valid cell is not detected by the RSSI scan, it may only be identified by performing an exhaustive search on every channel within the band                a process which is computationally expensive and time consuming.        
A well-performing RSSI scan reduces the need for exhaustive searches and therefore minimizes the time required by a user equipment to register with a network. It is therefore an aim of the invention to provide an efficient technique for performing an RSSI scan.
The RSSI scan result is primarily used by the user equipment to make autonomous decisions. In addition, the RSSI scan result may be reported to the network. In UMTS (universal mobile telecommunication services) mobile communication systems, it is therefore also known for user equipment to provide information on received signal strength to the network by compiling a RSSI (RSSI) report. The report may be compiled in the user equipment based on measurements associated with the signals received at the mobile terminal, and then transmitted to the network.
The transmission of such reports across the wireless link from the mobile terminal to the network side uses wireless resources. It is therefore also desirable to minimize the information necessary to be transmitted from the mobile terminal to the network side.
It is therefore a further aim of the invention to provide an improved technique for the provision of signal strength information in a communication system and for the generation and transmission of a received signal strength indication report in a UMTS mobile communication system.